Switched-mode power converters are widely used due to their high power conversion efficiency and fast dynamic response. They may be operated in one or more modes, notably in a PFM (pulse frequency modulation) or in a PWM (pulse width modulation) mode to convert electrical power and provide a regulated output voltage.
Switched-mode power converters are applied e.g. in battery charger systems. Such battery charger systems often have to limit the current at their input or at their output. At the input side, the input current has to be limited to not overload the source for charging (e.g. a wall adapter or a USB compliant source). At the output side, on the other hand, the output current should be limited to not damage the battery. To achieve this objective, a current regulation loop is needed for sensing and limiting the input current or output current.
Current regulation loops described in the state of the art are inactive until a current overload situation is detected. A current overload situation may occur in response to an initial event, such as e.g. a load change. In response to the initial event, the input or output current of a switched-mode power converter may quickly rise above a predetermined current threshold. The current regulation loop becomes active and reduces the respective current towards the predetermined current threshold.
The described unwanted rise of either the input current or the output current above the predetermined current threshold is also known as current over-shoot. At this, a current over-shoot may be characterized in terms of (a) a maximum current value measured after occurrence of the initial event or in terms of (b) a recovery time defined as the time the respective current exceeds an acceptable current value. The acceptable current value may be greater or equal to the predetermined current threshold.